Enterprise video conferencing is becoming a preferred way to conduct both one-on-one and group meetings. It enables employees to participate in a more relaxed and comfortable setting, whether they are working in the office or from home. Good enterprise video communication systems, such as telepresence systems and video conferencing systems (e.g., desktop video applications, etc.), can reduce travel expenditures and greatly increase productivity. This is, in part, because video feeds enable participants to interact in real time.
Video conferencing can take place within or across one or more domains. A domain may be a single organization, a closed user group, a company, or a community with logical (administration, policy, or management) and/or physical (network or security device) separation from the rest of the world. A single domain may include one or more zones with logical and/or physical demarcations. Examples of a single domain include, without limitation, an enterprise network with some local-area network endpoints, some Internet-connected endpoints and some mobile endpoints, or an enterprise network with endpoints within a single network that use different technology or protocols. Examples of different technology or protocols may include different types of signaling, such as SIP (Session Initiation Protocol), H.323, WebRTC (Web Real Time Communication), and TIP (Telepresence Interoperability Protocol), and different types of media codecs, such as H.264, H.265 and VP8.
When a communication session that includes video conferencing or telepresence is desired across multiple domains, or across zones within a domain, a series of problems arise that often prevent the communication session from being successfully executed, or even attempted. These problems create a perception that the communication session will not work or will be too difficult to achieve or costly, a perception that is often correct and, even when not, prevents the session from being attempted.
One category of problems that may arise relates to resource problems. Resource problems may include inadequate bandwidth, computing, bridging, or other resources for video sessions. These problems can occur because some prior-art systems do not optimize the use of such resources between different domains, and many of these resources are scarce, expensive, or shared.
Due to these and other limitations of at least some prior-art systems, inter-domain communication sessions that include videoconferencing or telepresence, usually fail for one or more of the following reasons:                i. users assume that their inter-domain communication session cannot include video conferencing or telepresence endpoints outside of their domains so they do not attempt it;        ii. users want to attempt an inter-domain communication session but do not know how to initialize and start the session (e.g., how to call the other parties, how to secure a bridge for multiple other parties, etc.); and        iii. users attempt an inter-domain communication session but the capabilities are too low, the costs are too high, or the user experience is too cumbersome and time consuming.        
Consequently, communication sessions that include inter-domain video are typically a very small percentage of today's enterprise video sessions. Similar problems are found inside large domains with multiple zones.
Accordingly, what is needed is an improved technique for executing and managing inter-domain communication sessions that include videoconferencing or telepresence, which makes it feasible for such sessions to be attempted and which makes attempted sessions successful, without at least some of the disadvantages in the prior art.